Accelerating system



Jan. 27, 1931.

H E. WHITE AC CELERA TING SYS TEN Filed Aug. 11. 1927' Forward 0 a b c de AINVENTVOR Harv/a f. Wh/fe ATTORNEY PM Jut 27, 1931 umran STATESPATENT time maom a warm, or wn-mmnc nous]: nae-rare a mus-mimic .vam

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swltches when the current rises above a pre-- determined value. Themeans, commonly utilized for obtaining such regulation comprisesdash-pots or similar mchanisms for giving an integral of time betweenthe closing of successivecontacts. Dash-pots however, requireconsiderable attention to keep them operatic'ally predetermining ingeficiently.

The object of my invention, generally stated, is to provide a motoraccelerating system which is not onl easily manufactured and reliable inoperation, but operates with- It is also the object of my invention toprovide a new and im roved control system for actuating automatically aplurality of contactors in a redetermined sequence.

Another object of my invention is to provide in a motor control systemfor automatthe operation ofthe accelerating means 0 the motor,independently of the motor itself.

Other objects of m invention will become apparent when the ollowingdescription is read in conjunction with the accompanying drawings,in.which Figure 1 is 'a diagrammatic view of a motor-control systemembodying the principal features of my invention, and,

Fig. 2 is a schematic diagram of the system shown in Fig. 1.

Referring'now to Figures 1 and 2, of the drawings, a motor 1 having anarmature 2 and a series fieldswind 3 is connected toa source of powersupply y means'of a double-poleswitch 4. through a ,set of reversingswitches-5,6, 7 and 8 and a starting resistor 9, which in thisapplication is divided into four sections 10, 11, and 13. The shunt- '1out the use of dash-pots or such mechanism;

ing of the sections of resistor is accomplished by'means of a pluralityof accelerating contactors 14, 15, 16 and 17. In order to control theoperation of the reversing contactors and the accelerating contactors, amanually op erable switch 19, and an auxiliary motor 20 are provided.

As referred to hereinbefore, the motor 1 Y ma beo is' esire be termedthe forwarddirection, the reverscontactors '5 and 8 are actuated toestab- 11s a c rcuit from the line conductor 21 through the series fieldwindin 3, conductor 22, the interlock on the reversing contactoror-switch 5, conductors 23-, 24, the armature erated in eitherdirection. When it ing contactor 8 and conductors 27 and 28 to theopposite lineconductor 29. Assuming that it s desired to run the motorin the opposite direction, then the reversin contactors 6 and 7 areclosed to establish a circuit from the line conductor 21 throu h theseries field winding 3, conductors 22 and 30, the interlock on thereversing contactor 7, conductor 26, the starting resistor 9, conductor25, the armature 2 of the motor 1, conductors 24 and 23, the interlockon the reversi contactor 6 and conductor 28 to the opposite lineconductor 29.

Circuits for controlling the operation of the reversing contactors 5, 6,7 and '8 are established through the manually operated controller 19 asshown in detail in Fig. 1. In this system, the reversing contactors 5and 8 are closed at the same time in order to o rate the motor in theforward directions E 'he manually-operable controller 19 is thrown to.the sition a in the forward direction, to esta lish an actuatingcircuit for the contactors 5 and 8 ,which circuit may be traced fromline-conductor-21 through conductor 31, the actuating coils 5a and 8aofthe' reversing contactors 5 and 8, respectively, connected in parallelrelation, conductors 32 and 33, segments 34 and 35 on the controller 19,conductors 36 and 28 to line conductor 29. Therefore, when thecontroller is thrown to the first position a in the forward direction,

to operate the motor 1 in what will I 2 of the motor 1, conductor 25,the resistor 9, conductor 26, the interlock on the revers-' thecontactors and 8, for efiecting forward operation of the motor, will beclosed.

In order to operate themotor m the reverse direction, the controller 19is thrown to the with the load and size of the motor.

and 28 to line conductor 29. When the con tactors 6 and 7 are closed,the motor 1 is rotated in the reverse direction.

When starting a large motor, it is common practice to connect a startingresistor such as resistor 9 in series relation with the armature of themotor to prevent excessive starting currents, and the motor is broughtup to full speed by decreasing the resistance in the motor circuit bysteps, in accordIance t is also common practice to accomplish this byemploying magnetic contactors or switches which are regul ted to beactuated in successive steps as the nature of the operation requires. Inthis system, the acceleratingcontactors or switches 14, 15, 16 and 17are provided to short-circuit the sections of the resistor.

In order that these accelerating contactors may be utilized toshort-circuit sections of the resistor 9, actuating coils 14a, 15a, 16aand 17 a, and the holding coils 14b, 15b, 16b

and 17?), are provided for operating the accelerati'ng contactors 14,15, 16 and 17, respectively. Theactuatin coils 14a to 17a inclusive,maybe connected-across the source of supply, through themanually-operated controller 19. The manual controllerv 19, in thisillustration, is constructed so that the various actuating coils may bedisposed to be energized in any desired order in accordance with thepositions, I), 0, d and e, or 6' 0, d and e, to which the controller maybe actuated, but in order that the sequence of operation will not dependupon the actuation of thecontroller 19 alone, the holding coils 14?),15b, 16b and 17 b are provided on the accelerating switches, orcontactors 14, 15, 16 and 17 respectively, and to regulate the currentflowing through these coils to pro vide the proper operation of theaccelerating contactors, they are energized in a circuit relation withthe armature of a small auxiliary motor 20, which has a shunt fieldWinding 61 connected directly across the line conductors 2 and 29.

The circuit through the holding coils 145, 15b, 16b and 17?) and thearmature 62 of the auxiliary motor 20, maybe traced from the energizedconductor 25 through a portion of resistor 9, moving contact 40,armature 62 arenas? of the auxiliary motor 20, conductor 41, the coils146,156, 166 and 17b, the accelerating contactors or switches 14, 15, 16and 17 respectively, to conductor 42. It will be observed'that circuits,as previously traced, are established from conductors 42 and 25 wheneither of the pair of reversing contactors'5 and 8, and 6 and 7 areclosed.

It is well known that when a motor is first started that a lar e currentwill be drawn by the armature o the motor,- and this char-- acteristicis taken advantage of in this invention, 1tbe1ng utilized in connect1onwith the "auxiliary motor whichfunctions as a.

valve for regulating the flow of current in the holding coils 14b, 15b,16b and 17 b, for holding the accelerating contactors 14, 15, 16 and 17,respectively, open against the pull of their actuating coils 14a, 15a,16a and 17a. It will be readily seen that as the auxiliary motor isbrought up to speed, its counter electromotive force will increase andthe current flowing through the holding coils in series therewith willdecrease, permitting the actuating coils to close the acceleratingcontactors or switches. The holding coils'and the actuating coils may bedesi ed to react to various currents, thereby o taining the propersequence of operation of the accelerating contactors.

It will be .readily understood in view of this, that the operation ofthe accelerating contactors will be made dependent upon the operation ofthe auxiliary motor, and also independent of the operation of the mainor work motor itself.

Various means may be provided for slowing up the starting of theauxiliary motor such as the fly wheel 44 mounted on the shaft motonthecurrent flowing through the holding coils may be varied or regulated.

in the invention, as can be observed in this application, I haveaccomplished the control of circuit flowing in the motor by connectingthe auxiliary motor to the source through the resistor 9 lay means of anadjustable contact 40 whereby the amount of resistance in the auxiliarymotor circuit can be varied to further regulate the effect of theholding coils on the accelerating contactors to meet quently desirableto be able to vary the line work motor.

Consistent with the theory of the invention, all of the actuating coils14a, 15a, 16a and 17a may be energized at the same time the work motoris started, without varying the effect of the holding coils which retarand predetermine the period of sequence of the accelerating contactors.In this application, however, it will be noted that the controller 19 isconstructed so that the operating coils 14a, 15a, 16a and 17a areenergized, in sequence as the controller 19 is moved ast the points b,0. J and e, in the forwar direction, or past the points 6, c, d and e inthe backward direction.

The energizing circuits of the actuating coils, when connected inparallel relation, may be traced from the line conductor 21 throughconductor 31, the actuating coils 14a, 15a, 16a and 17a, the conductors46,47, 48 and 49 to the contact segments 50, 51, 52 and 53,respectively, on the controller 19 and the contact segment 35 or 39,depending upon the position of controller 19 and through the conductors36 and 28 to the other lineconductor 29.

Therefore, the work motor may be operated with as many ections of theresistor 9 in series with the armature of the work motor as is desired.If the motor is used in connection with hoists or elevators, it is quitefrevoltage impressed uponthe motor.

-When the resistor sections 10, 11, 12 and 13 are shunt d, the currentwill flow throu h conductors 54, 55, 56 and 57, respectively.

It will be understoodthat in a system of this nature embodying myinvention that by means of the holding coils and the variable method ofimpressing different voltages upon the auxiliary motor that the periodselapsing between the successive steps in short-circuiting a section ofthe resistor through the operation of the accelerating switches orcontactors can be greatly varied and readily adapted to ractically anyapplication where motor acce erationof this 0 aracter is desired. I

While I have described my invention in connection. with one particularapplication, it will be understood that I do not wish to limit myself tothe specification or details as there are numerous changes which may bemade without departing from the spirit of my invention.

I claim as my invention:

1. In a control system, in combination with an electric work motor, aplurality of accelerating switches for thework motor, means forenergizing the actuating coils of the accelerating switches and meanscomprising a holding coil on each switch connected in series relationwith an auxiliary motor for retarding the operation of the acceleratingswitches in accordamle with the urrent-flowing thro gh i it theauxiliary motor and means for regulating the initial current flowingthrough the auxiliary motor. 7

2. In a control system, in combination with a work motor having astarting resistor,

a source of power for the motor, a lurality of electro-magnetic switchesfor se ectivel shunting portions of the resistor to acce erate themotor, said switches being provided with restraining coils, acircuit'for connecting the restraining coils across the power source,and an auxiliary motor for controlling the operation of the switches,said motor being disposed to control the amount of current flowlngiinthe coil circuit.

3. The combination with an electric motor, a source of power, a startingresistor for the motor, a switch for shunting the resistor, said switchbeing provided with a closing coil and a lockout coil, means forconnecting the coils to the power source, and means connected .in seriesrelation to the lockout coil for automatically varying its energizationfrom a maximum to a minimum to thereby efiect the release of the switchwithin a predetermined time interval subsequent to the energization ofthe motor.

tion, a main motor, a starting resistor for the motor, a plurality ofswitches disposed to shunt difl'erent sections of the resistor, saidswitches being provided with closing and restraining coils, manuallyoperable means for controlling the energization of the closing coils,and an auxiliary motor responsive to the energization of the main motorfor controlling the current flowing in the restraining coils, saidauxiliary motor being disposed to permit a relatively large initialcurrentto flow through all of said restraining coils, and graduallyreduce the said coil current to efiect the closure of the shuntingswitches in. a predetermined operating sequence.

5. In a motor-control system, in combination, a source of power, a. workmotor disposed to be connectedto the source of power,

'a starting resistor for the motor, a switch provided with a closingcoil for shunting the starting resistor, a circuit for actuating theswitch connected across the source of power for energizing the closingcoil, means energized from the power source for opposing the operationof the switch, and an auxiliary motor cooperative with the opposingmeans for controlling the operation of the switch.

6. In a control system, in combination, .a

source of power, a work motor disposed to be connected across the powersource, a'starting resistor for the work motor, a switch provided with aclosing coil for shunting the resistor to accelerate the work motor, acircuit for energizing the closing coil to actuate the switch,current-responsive means for biasing the switch to the open position, anauxiliary motor for controlling the current flowing. in thecurrent-responsive biasing means in accordance withvariations of itscounter-electromotive force, thereby to g'overn the closing operation ofthe shuntin switch independently of the load on the wor motor.

, 7. In a control system, in combination, a 1 work motor, a startingresistor for the motor, a source of power, means operable to connect themotor and starting resistor across the source of power, bridgingswitches for the resistor, said switches being provided with dif-' 1ferentially-acting operating coils, a master switch operable to controlthe energization of certain of the operating coils to eflectresistor-bridging operations, 7 an auxiliary motor connected inshunt-circuit relation 2 with a portion of the resistor and inseriescircuit relation to *the other operating coils of the bridgingswitches for varying the energizing current of said coils to govern theclosing operation of said switches, and energy-absorbing means disposedto retard the acceleration of the auxiliary motor.

8. In a control system, in combination, a work motor, a startingresistor for the motor, a sourceof power for the motor, means operableto connect the motor and starting resistor across the source of power, aplurality of bridging switches for the resistor, said g switches beingprovided with differentiallyrelated actuating coils, means forindividually energizing certain of the actuating coils to effect aclosing-operation of the bridging switches, and an auxiliary motorvariably connected across the starting resistor having an armature inseries-circuit 4o relation with the coils oppositely related to theindividually energized coils to restrain the closing operation of thebridging switches in accordance with the variations of the auxiliarymotor current. In testimony whereof, I have hereunto subscribed my namethis 3rd day of August,

HAROLD E. WHITE.

